X3DImporter.cpp advertises itself as able to open .x3db (compressed X3D) files:

    "x3d x3db"

But attempting to open simple official sample .x3db file HelloWorld.x3db fails with error:

Validation failed: aiScene::mNumMeshes is 0.  At least one mesh must be there

Does anyone know if this ever worked?

In any case, should probably comment out .x3db format pending restoring (or initial implementation) of the feature.

(Small model HelloWorld_x3db.zip attached directly in case above website goes away)